There are lots of microsSD extenders, converters and sniffers that I use to look at signals while debugging. Look for something like this on ebay.
They tend to be about $3.50
I find boards that allow me to...
Paul,
I stopped development of 16-bit Unicode when I discovered how hard it was to use. I already have decided that the next attempt would be UTF8 based.
The case problem is next. FAT16/FAT32 LFN is ambiguous....
I want providers of Arduino compatible systems to support standard Arduino functions. When I hit The Board Manager Tab I see over thirty board support packages. Not to mention things like PlatformIO.
Something like...
I wrote SdFat with the intention of better Unicode support but the underlying Arduino system make this difficult. Even supporting 8-bit as opposed to 7-bit ASCII is difficult since this require ANSI code pages.
...
I know about digitalWriteFast().
My question is about digitalWrite(). I am trying to write simple examples for all Arduino boards and Teensy 4.1 has this strange digitalWrite() property.
I looked at the code and...
I have been using digitalWrite() with a scope to time various operations in a new version of ChibiOS/RT. I first characterized digitalWrite() timing with this program:
void setup() {
pinMode(LED_BUILTIN,...
Release of SdFat is not related to Teensy. I like playing with Teensy but the overwhelming number of users are on other boards. Most of the mods in 2.0.5 will be for other systems.
I will be adding more support for...
I have posted the mods to the Teensy SDIO driver that allow fast simple loggers and the ring buffer for use in SRAM_L/SRAM_U on Teensy 3.6.
Try the TeensyDmaAdcLogger and TeensySdioLogger examples.
Enable this...
I posted a new version of SdFat-beta with the drive strength mod. It also has two examples that demonstrate new features in the Teensy SDIO driver.
Try the TeensyDmaAdcLogger and TeensySdioLogger examples.
I posted SdFat-beta with the new Teensy SDIO driver and two examples that demonstrate fast data logging using the new driver.
Try the TeensyDmaAdcLogger and TeensySdioLogger examples.
I have not updated UsbFat for six years. I have been meaning to add an example of USB storage to the current SdFat. This example shows how to use any block device with SdFat.
The driver uses a USB shield library...
I set the drive strength to 7 and looked at the SD CLK signal with a SD sniffer board. It is really being driven. The noise I made with scope probes only caused a data error once.
I suspect the error occurred when...
I am testing with 7 for the soon, I hope, release of the next beta. I have had lots of setbacks with fixes for cards that are very popular.
I am feeling good about mods to the Teensy driver. On Teensy 4.1 busy test...
The RingBuf class can be used in an ISR. I did a ping-pong ADC DMA test with Teensy 3.6 over-clocking the ADC and am able to log 6MB/sec.
Here is a link to that demo.
...
I have an example using SdFat for USB mass storage with a Mega ADK. I once posted "UsbFat" on github but found almost no interest. I think it was too early and the ADK was never popular.
Unfortunately the source buffer comes from the Print class and the destination buffer alignment depends on how many bytes have been written to the file.
I tested the above on a demo of a data logger that uses mods I...
There is another possible solution. SdFat keeps an index that is used to update the directory entry. This can be used to open files.
Long ago I wrote an example using open by index to test the idea. I just tried...
This seems to work. It is efficient except at the 0X20000000 boundary.
// Tensy3 memcpy
inline bool is_aligned(const void* ptr, uintptr_t alignment) {
auto iptr = reinterpret_cast<uintptr_t>(ptr);
return...
I have written a ring buffer class for buffering data during SD busy time. It works well if I use it for buffering full sectors. I have declared the buffer array like this. Size is a multiple of 512 bytes so everything...
Could you tell me what driver strength mods you think would work and I will include them in my tests. I have a number of Tennsy 4.1 and 3.6 boards running tests on my new Teensy driver mods.
I am in the process of...
The problem with scanning a directory backwards is that a file has an variable number 32 byte entries and they are designed to be scanned in the forward direction. For example in exFAT the set count is in the first...
You need to test any driver mod with files of at least 8 GiB on the popular SD cards from Samsung, Sandisk and the new Kingston Canvas Plus. I also test on older cards. You need to use a variety of write patterns...
I have been working on new features for SdFat. Two are useful for Teensy 3.6 and Teensy 4.1.
The first is a ring buffer that is tightly integrated with SdFat and can be called from an ISR. As a test, I did a DMA...
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